1. Field of the Invention
The present invention is related to a digital signal-input/output socket structure, and especially to a digital signal-input/output socket structure specific for plugging connection of a core post of an RCA plug with a characteristic impedance of 75 Ω suiting electric connection of digital and video signal lines etc. of an audio and video unit, it can make the characteristic impedances of the signal lines of the two ends of the socket structure and the RCA plug respectively match with each other after connecting of the socket structure with the plug, thereby signals can be accurately transmitted.
2. Description of the Prior Art
Generally, digital signal interfaces are divided into optical fibers and RCA coaxial digital lines; mostly a standard connector for coaxial digital lines is a normal BNC head with a characteristic impedance of 75 Ω (ohm), it is mated with a coaxial cable of 75 Ω to assure correct signal transmission without loss. However, coaxial lines sold in the markets presently all use RCA plugs, by the fact that initially RCA designs for transmitting audio signals, RCA plugs are less suitable to transmit digital signals by the reason that this may have a phenomenon of attenuation, the change in the characteristic impedance of them will have quite bad affection to digital signal transmitting.
Household machines normally use RCA plugs and sockets for coaxial inputting/outputting; as is shown in FIG. 5, an RCA plug “a” has its anode and cathode separated with an insulating separation layer “b” as a separating medium. A core post of the RCA plug “a” is made coarser in favor of insertion and extracting and being advantageous in not being subjected to bending and deforming, but this renders the characteristic impedance of the RCA plug “a” unable of reaching 75 Ω, and thereby the characteristic impedances of the two ends respectively of the RCA plug “a” and a digital signal-input/output socket “d” can not match with each other, this will make the output quality of digital signal transmitting be lowered and the requirement of acquiring its characteristics will be unable to meet.
In view of these, the inventor provides the present invention based on his professional experience of years and repeated experiments and tests in order that the characteristic impedances of the signal lines on the two ends can match with each other after connecting of the digital signal-input/output socket structure with the core post of the RCA plug with characteristic impedance of 75 Ω, thereby signals can be accurately transmitted.